247222-67-9Relevant academic research and scientific papers
Acid-base adducts of catalytically active titanium(IV) lewis acids
Larsen, Andrew O.,White, Peter S.,Gagne, Michel R.
, p. 4824 - 4828 (2008/10/08)
A series of monomeric Lewis acid-base adducts of the Diels-Alder catalyst Ti(O-2,6-Me2C6H3)2Cl2 have been synthesized from bidentate diphosphines and diamines, Ti(O-2,6-Me2C6H3)2Cl 2L2 (L2 = dmpe, depe, dpeda, and dmeda). X-ray crystal structures of Ti(O-2,6-Me2C6H3)2Cl 2(dmpe) and Ti(O-2,6-Me2C6H3)2Cl 2(dpeda) establish a distorted octahedral coordination environment with trans-chloride ligands. Bidentate ligands that were also studied but did not form isolable complexes with the Ti(IV) Lewis acid include dppe, tmeda, and binam. Through pairwise exchange reactions a qualitative ranking of relative bidentate ligand binding strengths to the Lewis acid were obtained (dmeda ≥ dpeda ≥ dmpe ≥ depe > tmeda > binam > dppe). The ranking is readily rationalized using hard-soft electronic arguments except for tmeda, which requires that unfavorable steric interactions be invoked.
